1. Field of the Invention
This invention relates to contraceptive devices and particularly to intrauterine contraceptive devices.
2. Description of the Prior Art
U.S. Pat. No. 3,533,406 discloses an intrauterine contraceptive device having a "T" shape. The device is completely placed into the endometrial cavity where the end of the stem extends toward the cervical os when the cross bar of the "T" lies at the fundus of the uterus. The contraceptive efficacy of the "T" device has proven unacceptable for many families. As a result, the "T" device has been used in many applications as a carrier for contraceptive chemicals such as copper. It is believed that the relatively small cross section of the stem of the "T" device prevents it from having the desired contraceptive effect. The so-called "7" shaped devices have produced effects nearly identical to the "T" devices. Both the "T" and "7" devices are lightweight and embed somewhat in the endometrial tissue. Expulsion rates and bleeding are modest, primarily because of the form and size of the devices.
U.S. Pat. No. 3,881,475 discloses an intrauterine contraceptive device having a pair of loops extending in opposite directions from a common stem. Each loop has a free end. This design has attempted to provide a device wherein the loops are capable of more readily conforming to the walls of the uterine cavity and are soft enough to move with the uterine walls as they move or contract. Higher expulsion rates and removal rates are reported with use of the device.
U.S. Pat. No. 3,937,217 provides an intrauterine contraceptive device which resembles the "T" device but which has a loop formed in the end of the stem and has a less rigid crossbar construction. This patented device has as its primary object the reduction of bleeding, involuntary expulsion and occasional perforation into the cervix associated with the "T" device. Other intrauterine contraceptive devices having similar constructions are described in U.S. Pat. Nos. 3,454,004; 3,457,915; 3,810,456 and 3,842,826.
Thus, it becomes an object of the present invention to provide an intrauterine contraceptive device having the advantages associated with the above-described devices, but with increased contraceptive efficacy, lower expulsion rates and less bleeding and pain for the patient.